Why Excavator Tooth Pins Keep Falling Out?

If you’ve been in the construction or earthmoving business for a while, you’ve probably faced it — that annoying moment when your excavator tooth pin falls out during work. One minute everything’s fine, the next, your bucket tooth is gone! Not only does this stop your job, but it can also lead to expensive repairs.

So, why does it happen? And more importantly, how can you prevent it? Let’s break it down step by step.

1. Poor Fit or Wrong Size

The most common reason why excavator tooth pins fall out is using the wrong size or incorrect model.
Every excavator brand — whether it’s CAT, Komatsu, Hitachi, Volvo, or Hyundai — has a slightly different tooth and adapter design.

When the pin doesn’t match perfectly, it won’t lock securely, even if you hammer it tight. Once the bucket starts vibrating under load, the pin starts moving… and soon, it just slips out.

👉 Quick Tip: Always check the part number or consult your supplier before ordering new pins.

2. Worn or Damaged Tooth Adaptor

Over time, the adapter slot where the pin sits can wear down due to friction and impact. A worn slot means the pin won’t sit snugly anymore, no matter how hard you try to fix it.

You can easily check this by removing the tooth and examining the hole edges — if they’re uneven or rounded, it’s time for a replacement.

It might sound like extra cost, but honestly, replacing a worn adapter is way cheaper than losing teeth mid-operation.

3. Poor Installation

Let’s face it, sometimes the problem isn’t the part — it’s the installation.
If the pin wasn’t aligned properly, or if it wasn’t fully seated, it’s bound to fall out after a few hours of digging.

During installation, always make sure the holes on the tooth and adapter are aligned perfectly before inserting the pin. A light hammer tap should secure it — don’t overdo it!

Oh, and here’s a fun fact: most loose tooth pins come from over-hammering, which bends the pin slightly and weakens its grip.

4. Using Low-Quality Pins

Let’s be honest — cheap, low-quality pins are a false economy.
They might look fine at first, but poor metallurgy and weak heat treatment mean they can deform easily under pressure.

A bent or cracked pin loses its locking power quickly. That’s why professional operators always prefer high-strength alloy steel pins made by trusted manufacturers like Nan’an Jinxin Machinery Co., Ltd.

Our pins are precision-machined, heat-treated, and tested for durability to match OEM standards.

5. Lack of Maintenance

Even the best parts fail if you don’t maintain them.
Regularly check the tooth and pin assembly before and after shifts. If you notice looseness or movement, replace the pin immediately.

Also, keep the locking area clean — mud or sand buildup can prevent proper locking, making the pin more likely to slip out.

6. How Jinxin Machinery Solves the Problem

At Nan’an Jinxin Machinery Co., Ltd., we know how frustrating it can be when tooth pins fail in the field.
That’s why we design and produce excavator tooth pins that perfectly fit various brands and models, including CAT, Komatsu, Volvo, Hitachi, Doosan, and Hyundai.

Each pin undergoes strict quality control, precision machining, and surface hardening to ensure a secure fit and long service life.

What’s more — our company offers after-sales support to guide customers through installation and maintenance. If your pin falls out often, our technicians can help analyze why and recommend the best solution.

We’re not just a manufacturer; we’re your long-term machinery partner.

Excavator tooth pins falling out might seem like a small issue, but it can cause major downtime and cost.
By choosing the right fit, installing it properly, and maintaining it regularly, you’ll keep your excavator performing at its best.

For durable, perfectly fitting excavator tooth pins, contact Jinxin Machinery — your reliable China manufacturer and supplier for all major excavator models.